This is the VOA Special English SCIENCE REPORT.
British scientists may have discovered the reason why red wine appears to protect the heart. They say natural chemicals found in red wine appear to protect against blocked blood passages. The chemical substances are called polyphenols. They come from the outer covering of grapes. They are not present in other alcoholic drinks.
Researchers from the William Harvey Research Institute at the London School of Medicine and Dentistry carried out the study. The findings are published in Nature magazine.
The scientists say their discovery explains why many people in southern Europe can eat fatty foods and still have a low risk of heart disease. People in France, for example, have lower rates of heart disease than Americans do. Yet the traditional French diet includes butter, cheese and other foods high in cholesterol.
This led the British scientists to examine another important part of the French diet -- red wine. Several earlier studies have suggested that people who drink moderate amounts of alcohol may reduce their risk of heart disease.
The British team experimented with cells from the blood vessels of cows. The scientists studied the effects of twenty-three kinds of red wine on the cow cells. They found that polyphenols from all of the red wines stopped production of a protein called endothelin-one. This protein causes blood vessels to become smaller. Scientists believe endothelin-one is linked to hardening of the blood vessels, which is a cause of heart disease.
The scientists found that the decrease in endothelin-one levels was linked to the amount of polyphenols in the wines. The red wine known as Cabernet Sauvignon seemed to have the greatest effect.
The British team performed similar experiments with two other kinds of wine, white and rose. These wines contain little or no polyphenols because the grape skins are removed before the wine is made. White and rose wines had no effect on endothelin-one levels.
The scientists also studied the effect of non-alcoholic juice made from red grapes. They found that grape juice slowed the production of endothelin-one, but was much less effective than the red wines.
The scientists say people who already drink wine might consider drinking red wine to increase their protection against heart disease.
This VOA Special English SCIENCE REPORT was written by George Grow.